PSAM 16 - Session M03 Overview

PSAM 16 Conference Session M03 Overview

Session Chair: Vincent Paglioni (paglioni@umd.edu)

Paper 1 JJ250

Lead Author: Andreas Bye Co-author(s): Jeffrey A. Julius, jjulius@jensenhughes.com Dr. Ronald Boring, ronald.boring@inl.gov

HRA Challenges in New Nuclear Power Plant Designs
Digital instrumentation and control systems are being added to operating nuclear power plants (NPP), and included in the designs of the next generation of NPPs. Further, the newer advanced reactors are not only incorporating digital systems, but they are also increasing the amount of automation to improve plant safety and to decrease the reliance on human operators. In each of these cases, advancements in system design such as instrumentation, controls, automation, and data collection have significantly altered the human-machine interface. Human factors insights related to tasks, procedures, training, and allocation of functions help to improve safety and reliability. Operating experience with NPPs and other systems tells us that in addition to improvements, the design is not guaranteed to be free from errors. In order to evaluate the effectiveness of these improvements in the digital I&C systems, a human reliability analysis (HRA) as part of a risk assessment can provide insights into what is likely to go wrong and the consequences of errors. For the first generation of power plants in the USA, the risk assessment and HRA were developed after the plants were built and operating. In order to further improve the safety and reliability of new plants, an approach that combines these two disciplines during the design and pre-operational phase is recommended. This paper outlines the concept for this approach, discusses advantages and potential disadvantages of digital instrumentation, controls, automation, and data collection systems, and recommends a technology neutral approach to applying HF and HRA techniques to improve NPP safety and reliability. A number of challenges in todays’ HRA and HF processes and methods are discussed, and also the way in which these challenges might change in future new designs.

HRA Challenges in New Nuclear Power Plant Designs

Digital instrumentation and control systems are being added to operating nuclear power plants (NPP), and included in the designs of the next generation of NPPs. Further, the newer advanced reactors are not only incorporating digital systems, but they are also increasing the amount of automation to improve plant safety and to decrease the reliance on human operators. In each of these cases, advancements in system design such as instrumentation, controls, automation, and data collection have significantly altered the human-machine interface. Human factors insights related to tasks, procedures, training, and allocation of functions help to improve safety and reliability. Operating experience with NPPs and other systems tells us that in addition to improvements, the design is not guaranteed to be free from errors. In order to evaluate the effectiveness of these improvements in the digital I&C systems, a human reliability analysis (HRA) as part of a risk assessment can provide insights into what is likely to go wrong and the consequences of errors. For the first generation of power plants in the USA, the risk assessment and HRA were developed after the plants were built and operating. In order to further improve the safety and reliability of new plants, an approach that combines these two disciplines during the design and pre-operational phase is recommended. This paper outlines the concept for this approach, discusses advantages and potential disadvantages of digital instrumentation, controls, automation, and data collection systems, and recommends a technology neutral approach to applying HF and HRA techniques to improve NPP safety and reliability. A number of challenges in todays’ HRA and HF processes and methods are discussed, and also the way in which these challenges might change in future new designs.

Paper JJ250 | Download the paper file. | Download the presentation PowerPoint file.

Name: Andreas Bye (Andreas.Bye@ife.no)

Bio: Program manager for the OECD NEA Halden HTO Project from January 2021. More than 30 years experience from IFE and the OECD Halden Reactor Project. Main interests: Human-Technology-Organization, HRA, Human Factors

Country: NOR
Company: IFE, Institute for Energy Technology
Job Title: Chief Scientist, Programme Manager, OECD NEA Halden HTO Project

Paper 2 AA176

Lead Author: Ahmad Al-Douri Co-author(s): Camille S. Levine clevine1@umd.edu Katrina M. Groth kgroth@umd.edu

Identifying Human Failure Events (HFEs) for External Hazard Probabilistic Risk Assessment
In recent years, several advancements in nuclear power plant (NPP) probabilistic risk assessment (PRA) have been driven by increased understanding of external hazards, plant response, and uncertainties. However, major sources of uncertainty associated with external hazard PRA remain. One source discussed in this study is the close coupling of physical impacts on plants and overall plant risk under hazard events due to the significant human actions that are carried out to enable plant response and recovery from natural hazards events. This makes human reliability and human-plant interactions important elements in to consider in enhancing PRA to address external hazards. One of the challenges in considering human responses is that most existing human reliability analysis (HRA) models, such as SPAR-H and THERP, were not developed for assessing ex-control room actions and hazard response. To support this new scope for HRA, HRA models will need to be developed or modified to support identification of human activities, causal factors, and uncertainties inherent in external hazard response, thereby providing insights regarding event timing and physical event conditions as they relate to human performance. In this study, the first step of such work is performed by identifying human failure events (HFEs) for human response to flooding hazards. These HFEs are human actions or inactions that are involved in human response to flooding hazards and could contribute to the loss of a critical function for the plant in the scenario being examined. Several resources are used to identify these HFEs, including flooding reports from the Nuclear Regulatory Commission (e.g. NUREG/CR-7256: Effects of Environmental Conditions on Manual Actions for Flood Protection and Mitigation), interviews with experienced PRA and HRA analysts, and tabletop walkdowns of flooding scenarios with a project team. Also, task decomposition analysis, using the cognitive-based Phoenix HRA model, are also used to identify HFEs. This paper will discuss early results of these analysis.

Identifying Human Failure Events (HFEs) for External Hazard Probabilistic Risk Assessment

In recent years, several advancements in nuclear power plant (NPP) probabilistic risk assessment (PRA) have been driven by increased understanding of external hazards, plant response, and uncertainties. However, major sources of uncertainty associated with external hazard PRA remain. One source discussed in this study is the close coupling of physical impacts on plants and overall plant risk under hazard events due to the significant human actions that are carried out to enable plant response and recovery from natural hazards events. This makes human reliability and human-plant interactions important elements in to consider in enhancing PRA to address external hazards. One of the challenges in considering human responses is that most existing human reliability analysis (HRA) models, such as SPAR-H and THERP, were not developed for assessing ex-control room actions and hazard response. To support this new scope for HRA, HRA models will need to be developed or modified to support identification of human activities, causal factors, and uncertainties inherent in external hazard response, thereby providing insights regarding event timing and physical event conditions as they relate to human performance. In this study, the first step of such work is performed by identifying human failure events (HFEs) for human response to flooding hazards. These HFEs are human actions or inactions that are involved in human response to flooding hazards and could contribute to the loss of a critical function for the plant in the scenario being examined. Several resources are used to identify these HFEs, including flooding reports from the Nuclear Regulatory Commission (e.g. NUREG/CR-7256: Effects of Environmental Conditions on Manual Actions for Flood Protection and Mitigation), interviews with experienced PRA and HRA analysts, and tabletop walkdowns of flooding scenarios with a project team. Also, task decomposition analysis, using the cognitive-based Phoenix HRA model, are also used to identify HFEs. This paper will discuss early results of these analysis.

Paper AA176 | Download the paper file. | Download the presentation PowerPoint file.

Name: Ahmad Al-Douri (aaldouri@umd.edu)

Bio: I have been a postdoctoral researcher at the University of Maryland Systems Risk and Reliability Analysis (SyRRA) lab since August 2021, supervised by Prof. Katrina Groth. Prior to that, I was astudent at Texas A&M University's Department of Chemical Engineering where I obtained a B.S. (2011), M.S. (2016) and Ph.D. (2021). I also hold a M.S. in petroleum engineering from Texas A&M University. My research interests include: process design and techno-economic assessment, process safety and reliability, and hydrogen systems risk and reliability.

Country: USA
Company: University of Maryland
Job Title: Postdoctoral Research Associate

Paper 3 K7325

Lead Author: Seungwoo Lee Co-author(s): Yongjin Lee, k730lyj@kins.re.kr Namchul Cho, namchul.cho@kins.re.kr

INSIGHTS FOR HUMAN RELIABILITY ANALYSIS METHOD GAINED FROM ROOT CAUSES ANALYSIS OF HUMAN ERROR EVENTS OCCURRED IN KOREA
Human error is known as dominant contributors to the safety of complex systems such as nuclear power plants(NPPs). In analyzing human error, both prospective approach whose purpose is to estimate the probability of human error in quantitative manner and retrospective approach whose purpose is to identify the root causes of human error in qualitative manner are used. Regarding prospective approach, various methods have been suggested to assess human reliability in field of risk assessment of nuclear power plants. Most of these approaches visits the results from retrospective approach to develop their own models for estimating human error probability or to describe mechanisms for human error. Also, it is notable that the qualitative analysis is used as one of the key steps in most of the prospective approaches. In this manner, this study aims to give insights for current HRA methods by investigating the results of retrospective approach. When human error occurs in Korea, investigators from KINS(Korea Institute of Nuclear Safety) analyzes the human error using HuRAM+( Human related event root causes analysis method plus) which was originally developed to identify the inadequate human actions occurred in NPPs. In using HuRAM+, investigators need to gather all the information regarding the events such as date of event occurrence, design of NPPs, procedures et al. Based on the information gathered, investigators identify the types of human error ; (1) Error of Omission or Error of Commission, (2) Mistake or Slip/Lapse or Violation, (3) Active or Latent and identify the location and the plant operational mode when the human error occurred. Finally, investigators identify the detailed root causes of the human error using error classification scheme in HuRAM+. To briefly explain error classification scheme, HuRAM+ has 3 categories which are (1) Task/System, (2) Organization/Safety Culture, (3) Etc and these 3 categories have hierarchical classifications for each category. For example, Task/System has 7 sub-categories which are ‘Procedures’, ‘Workload’, ‘Training/Education’, ‘Human-System Interface’, ‘Communication’, ‘Worker(Team)’ and ‘Supervisor’ and each sub-category has root cause items. The results of investigating 139 human error events occurred from 1978 to 2020 in Korea using HuRAM+ is analyzed to give insights to the HRA method. Specifically, these insights are given in the aspects of technical elements of HRA method such as performance shaping factors(PSFs) and etc. Finally, it is expected that more sophisticated HRA method can be developed using the insights gained from the investigating the results of prospective approach. Keywords: human error events, prospective approach, retrospective approach, root causes, insights, human error analysis method. References 1. J, Park et al. (2019). Remaining and emerging issues pertaining to the human reliability analysis of domestic nuclear power plants. Nuclear Engineering and Technology 51, 1297-1306 2. KINS/HR-1393, A study on the strategy enhancing the application of HuRAM+, 2015, Korea Institute of Nuclear Safety. 3. R.Boring, TOP-DOWN AND BOTTOM-UP DEFINITIONS OF HUMAN FAILURE EVENTS IN HUMAN RELIABILITY ANALYSIS, Proceedings of the Human Factors and Ergonomics Society 58th Annual Meeting - 2014

INSIGHTS FOR HUMAN RELIABILITY ANALYSIS METHOD GAINED FROM ROOT CAUSES ANALYSIS OF HUMAN ERROR EVENTS OCCURRED IN KOREA

Human error is known as dominant contributors to the safety of complex systems such as nuclear power plants(NPPs). In analyzing human error, both prospective approach whose purpose is to estimate the probability of human error in quantitative manner and retrospective approach whose purpose is to identify the root causes of human error in qualitative manner are used. Regarding prospective approach, various methods have been suggested to assess human reliability in field of risk assessment of nuclear power plants. Most of these approaches visits the results from retrospective approach to develop their own models for estimating human error probability or to describe mechanisms for human error. Also, it is notable that the qualitative analysis is used as one of the key steps in most of the prospective approaches. In this manner, this study aims to give insights for current HRA methods by investigating the results of retrospective approach. When human error occurs in Korea, investigators from KINS(Korea Institute of Nuclear Safety) analyzes the human error using HuRAM+( Human related event root causes analysis method plus) which was originally developed to identify the inadequate human actions occurred in NPPs. In using HuRAM+, investigators need to gather all the information regarding the events such as date of event occurrence, design of NPPs, procedures et al. Based on the information gathered, investigators identify the types of human error ; (1) Error of Omission or Error of Commission, (2) Mistake or Slip/Lapse or Violation, (3) Active or Latent and identify the location and the plant operational mode when the human error occurred. Finally, investigators identify the detailed root causes of the human error using error classification scheme in HuRAM+. To briefly explain error classification scheme, HuRAM+ has 3 categories which are (1) Task/System, (2) Organization/Safety Culture, (3) Etc and these 3 categories have hierarchical classifications for each category. For example, Task/System has 7 sub-categories which are ‘Procedures’, ‘Workload’, ‘Training/Education’, ‘Human-System Interface’, ‘Communication’, ‘Worker(Team)’ and ‘Supervisor’ and each sub-category has root cause items. The results of investigating 139 human error events occurred from 1978 to 2020 in Korea using HuRAM+ is analyzed to give insights to the HRA method. Specifically, these insights are given in the aspects of technical elements of HRA method such as performance shaping factors(PSFs) and etc. Finally, it is expected that more sophisticated HRA method can be developed using the insights gained from the investigating the results of prospective approach. Keywords: human error events, prospective approach, retrospective approach, root causes, insights, human error analysis method. References 1. J, Park et al. (2019). Remaining and emerging issues pertaining to the human reliability analysis of domestic nuclear power plants. Nuclear Engineering and Technology 51, 1297-1306 2. KINS/HR-1393, A study on the strategy enhancing the application of HuRAM+, 2015, Korea Institute of Nuclear Safety. 3. R.Boring, TOP-DOWN AND BOTTOM-UP DEFINITIONS OF HUMAN FAILURE EVENTS IN HUMAN RELIABILITY ANALYSIS, Proceedings of the Human Factors and Ergonomics Society 58th Annual Meeting - 2014

Paper K7325 | | Download the presentation PowerPoint file.

Name: Seungwoo Lee (k727lsw@kins.re.kr)

Bio: Bachelor degree: Nuclear Engineering at Hanyang university Master degree : Nuclear Engineering at Hanyang university - Probabilistic Safety Analysis Doctoral degree : Nuclear and Quantum Engineering at KAIST - Human Reliability Analysis, Human Factors Engineering Current job status : Joined Korea Institute of Nuclear Safety since 2013 Currently working as a principal researcher at department of severe accident and risk assessment Review PSA report submitted by utility etc.

Country: KOR
Company: Korea Institute of Nuclear Safety
Job Title: Principal Researcher

Paper 4 KS251

Lead Author: Jinkyun Park Co-author(s): Inseok Jang, isjang@kaeri.re.kr Jooyoung Park, jooyoung.Park@inl.gov Ronald L. Boring, Ronald.Boring@inl.gov Thomas A. Ulrich, thomas.ulrich@inl.gov

A framework to integrate HRA data obtained from different sources based on the complexity scores of proceduralized tasks
Since the TMI accident, it is evident that the PSA (Probabilistic Safety Assessment) or PRA (Probabilistic Risk Assessment) has been used as one of the representative techniques to enhance the safety of nuclear power plants (NPPs) by visualizing the catalog of potential hazards in a systematic way. Since human error represents one of the potential hazards, diverse HFEs (Human Failure Events) should be incorporated into the development of the PSA model. Typical HFEs include “the purpose of the task cannot be achieved” or “the task fails to be completed” [1]. Accordingly, in terms of conducting the PSA, it is indispensable to quantify the likelihood of HFEs (or Human Error Probabilities, HEPs). For this reason, many kinds of HRA (Human Reliability Analysis) methods have been proposed in the last several decades. In general, the HRA process can be done with three steps: (1) task analysis, (2) qualitative analysis, and (3) quantitative analysis. Brief explanations on these steps are as follows: “Task analysis is the process of collecting and analyzing relevant information on the major human actions considered in a PSA model. In qualitative analysis, performance shaping factors (PSFs) critical to error occurrences are analyzed in the context of each human action. PSFs refer to factors that influence human performance, including experience, stress, and task complexity. Lastly, based on the task analysis and qualitative analysis results, HEPs are estimated using quantitative analysis [2].” From this excerpt, it is obvious that the quality of information to be used in the HRA process (i.e., HRA data) is critical for ensuring the credibility of HRA results. This became the motivation of HRA data collection from many available sources including event investigation reports and simulator studies [3]. Unfortunately, it is also true that the quality of HRA data is one of the key limitations from the very beginning of an HRA method development [4, 5], it is critical to materialize how to soundly integrate a lot of HRA data spread out in the diverse sources. In order to address this issue, in this study, the framework of HRA data integration is investigated based on the complexity of proceduralized tasks. The underlying idea is to directly compare two sets of HRA data obtained from different sources (one came from the full-scope training simulator of NPPs and the other from a small-scale laboratory experiment using a simplified simulator such as INL’s Rancor Microworld). If there is a significant correlation between two sets of HRA data, then it is expected that we can have a relevant clue supporting how to integrate diverse HRA data. [1] Kirimoto, Y., Hirotsu, Y., Nonose, K., and Sasou K., 2021. Development of a human reliability analysis (HRA) guide for qualitative analysis with emphasis on narratives and models for tasks in extreme conditions, 53(2), p. 376-385 (https://doi.org/10.1016/j.net.2020.10.004) [2] Park, J., Boring, R. L., Ulrich, T. A., Lew, R., Lee, S., Park, B., and Kim, J., 2022. A framework to collect human reliability analysis data for nuclear power plants using a simplified simulator and student operators, Reliability Engineering and System Safety, 221, 108326 (https://doi.org/10.1016/j.ress.2022.108326) [3] Park, J., Jung, W., Kim, S., Choi, S. Y., Kim, Y., Lee, S. J., Yang, J. E., and Dang, V. N., 2014. A guideline to collect HRA data in the simulator of nuclear power plants, Korea Atomic Energy Research Institute, KAERI/TR-5206, Daejeon, Republic of Korea (written in English) [4] Swain, A. D., 1990. Human reliability analysis: Need, status, trends and limitations, Reliability Engineering and System Safety, 29(3), p. 301-313 (https://doi.org/10.1016/0951-8320(90)90013-D) [5] Hollnagel, E., 2005. Human reliability assessment in context, Nuclear Engineering and Technology, 37(2), p. 159-166

A framework to integrate HRA data obtained from different sources based on the complexity scores of proceduralized tasks

Since the TMI accident, it is evident that the PSA (Probabilistic Safety Assessment) or PRA (Probabilistic Risk Assessment) has been used as one of the representative techniques to enhance the safety of nuclear power plants (NPPs) by visualizing the catalog of potential hazards in a systematic way. Since human error represents one of the potential hazards, diverse HFEs (Human Failure Events) should be incorporated into the development of the PSA model. Typical HFEs include “the purpose of the task cannot be achieved” or “the task fails to be completed” [1]. Accordingly, in terms of conducting the PSA, it is indispensable to quantify the likelihood of HFEs (or Human Error Probabilities, HEPs). For this reason, many kinds of HRA (Human Reliability Analysis) methods have been proposed in the last several decades. In general, the HRA process can be done with three steps: (1) task analysis, (2) qualitative analysis, and (3) quantitative analysis. Brief explanations on these steps are as follows: “Task analysis is the process of collecting and analyzing relevant information on the major human actions considered in a PSA model. In qualitative analysis, performance shaping factors (PSFs) critical to error occurrences are analyzed in the context of each human action. PSFs refer to factors that influence human performance, including experience, stress, and task complexity. Lastly, based on the task analysis and qualitative analysis results, HEPs are estimated using quantitative analysis [2].” From this excerpt, it is obvious that the quality of information to be used in the HRA process (i.e., HRA data) is critical for ensuring the credibility of HRA results. This became the motivation of HRA data collection from many available sources including event investigation reports and simulator studies [3]. Unfortunately, it is also true that the quality of HRA data is one of the key limitations from the very beginning of an HRA method development [4, 5], it is critical to materialize how to soundly integrate a lot of HRA data spread out in the diverse sources. In order to address this issue, in this study, the framework of HRA data integration is investigated based on the complexity of proceduralized tasks. The underlying idea is to directly compare two sets of HRA data obtained from different sources (one came from the full-scope training simulator of NPPs and the other from a small-scale laboratory experiment using a simplified simulator such as INL’s Rancor Microworld). If there is a significant correlation between two sets of HRA data, then it is expected that we can have a relevant clue supporting how to integrate diverse HRA data. [1] Kirimoto, Y., Hirotsu, Y., Nonose, K., and Sasou K., 2021. Development of a human reliability analysis (HRA) guide for qualitative analysis with emphasis on narratives and models for tasks in extreme conditions, 53(2), p. 376-385 (https://doi.org/10.1016/j.net.2020.10.004) [2] Park, J., Boring, R. L., Ulrich, T. A., Lew, R., Lee, S., Park, B., and Kim, J., 2022. A framework to collect human reliability analysis data for nuclear power plants using a simplified simulator and student operators, Reliability Engineering and System Safety, 221, 108326 (https://doi.org/10.1016/j.ress.2022.108326) [3] Park, J., Jung, W., Kim, S., Choi, S. Y., Kim, Y., Lee, S. J., Yang, J. E., and Dang, V. N., 2014. A guideline to collect HRA data in the simulator of nuclear power plants, Korea Atomic Energy Research Institute, KAERI/TR-5206, Daejeon, Republic of Korea (written in English) [4] Swain, A. D., 1990. Human reliability analysis: Need, status, trends and limitations, Reliability Engineering and System Safety, 29(3), p. 301-313 (https://doi.org/10.1016/0951-8320(90)90013-D) [5] Hollnagel, E., 2005. Human reliability assessment in context, Nuclear Engineering and Technology, 37(2), p. 159-166

Paper KS251 | Download the paper file. |

Name: Jinkyun Park (kshpjk@kaeri.re.kr)

Bio:

Country: KOR
Company: Korea Atomic Energy Research Institute
Job Title: Principal Researcher